public override void Handle(CommandScheduled @event)
{
// An entry is considered committed once it has been written to persistant storage and replicated.
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new CommitEntry
{
EntryIdx = @event.LogEntry.Index,
EntryTerm = @event.LogEntry.Term
}
}).Wait();
@event.Command.Execute(_serviceLocator);
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new ApplyEntry
{
EntryIdx = @event.LogEntry.Index
}
}).Wait();
if (@event.CompletionSource != null)
{
@event.CompletionSource.SetResult(new CommandExecutionResult(true));
}
}
// TODO: Make this use same buffer and event as RpcLogWriter.
public void OnNext(ApplyCommandRequested data, long sequence, bool endOfBatch)
{
var appliedDifference = data.LogIdx - _node.Data.LastApplied;
var logsToApply = EnumerableUtilities.Range(_node.Data.LastApplied + 1, (int)appliedDifference);
foreach (var logIdx in logsToApply)
{
var command = _commandRegister.Get(_node.Data.CurrentTerm, logIdx);
// The term may have been increased before the command was applied. In which case, rely on log matching to fix.
if (command == null)
{
continue;
}
command.Execute(_serviceLocator);
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new ApplyEntry
{
EntryIdx = logIdx
}
}).Wait();
}
}
public RequestVoteResponse RequestVote(RequestVoteRequest voteRequest)
{
if (voteRequest.Term <= _node.Data.CurrentTerm)
{
return(new RequestVoteResponse
{
Term = _node.Data.CurrentTerm,
VoteGranted = false
});
}
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new SetNewTerm
{
Term = voteRequest.Term
}
}).Wait();
return(null);
}
public Task <CommandExecutionResult> ExecuteCommand <T>(T command) where T : IRaftCommand, new()
{
if (_node.CurrentState != NodeState.Leader)
{
throw new NotClusterLeaderException();
}
return(_commandPublisher.PublishEvent(
new CommandScheduled
{
Command = command
}));
}
public void OnNext(AppendEntriesRequested data, long sequence, bool endOfBatch)
{
if (!data.PreviousLogIndex.HasValue || !data.PreviousLogTerm.HasValue)
{
return;
}
if (data.PreviousLogIndex.Equals(_node.Data.CommitIndex))
{
return;
}
if (data.PreviousLogIndex > _node.Data.CommitIndex ||
data.PreviousLogTerm > _node.Data.CurrentTerm)
{
throw new InvalidOperationException(
"This command is invalid and should not be published to the buffer.");
}
var truncateCommandEntry = new TruncateLogCommandEntry
{
TruncateFromIndex = data.PreviousLogIndex.Value
};
using (var ms = new MemoryStream())
{
Serializer.SerializeWithLengthPrefix(ms, truncateCommandEntry, PrefixStyle.Base128);
_writeDataBlocks.WriteBlock(ms.ToArray());
}
_nodePublisher.PublishEvent(
new NodeCommandScheduled
{
Command = new TruncateLog
{
TruncateFromIndex = data.PreviousLogIndex.Value
}
});
}
public AppendEntriesResponse AppendEntries(AppendEntriesRequest entriesRequest)
{
// If the node term is greater, return before updating timer. Eventually an election will trigger.
if (_node.Data.CurrentTerm > entriesRequest.Term)
{
return new AppendEntriesResponse
{
Term = _node.Data.CurrentTerm,
Success = false
}
}
;
_timer.ResetTimer();
if (_node.Data.CurrentTerm < entriesRequest.Term)
{
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new SetNewTerm
{
Term = entriesRequest.Term
}
}).Wait();
}
if (_node.CurrentState == NodeState.Candidate)
{
_nodePublisher.PublishEvent(new NodeCommandScheduled
{
Command = new CancelElection()
}).Wait();
}
if (_node.CurrentState != NodeState.Follower)
{
throw new FaultException <MultipleLeadersForTermFault>(new MultipleLeadersForTermFault
{
Id = _node.Data.NodeId
});
}
if (_node.Data.Log[entriesRequest.PreviousLogIndex] != entriesRequest.PreviousLogTerm)
{
return(new AppendEntriesResponse
{
Term = _node.Data.CurrentTerm,
Success = false
});
}
_nodePublisher.PublishEvent(
new NodeCommandScheduled {
Command = new SetLeaderInformation
{
LeaderId = entriesRequest.LeaderId
}
});
// TODO: Buffer will be responsible for Log Truncating, Log Writing, Log Applying
_appendEntriesPublisher.PublishEvent(new AppendEntriesRequested
{
PreviousLogIndex = entriesRequest.PreviousLogIndex,
PreviousLogTerm = entriesRequest.PreviousLogTerm,
LeaderCommit = entriesRequest.LeaderCommit,
Entries = entriesRequest.Entries
});
return(new AppendEntriesResponse
{
Term = _node.Data.CurrentTerm
});
}
}
